The subject matter disclosed herein relates generally to clearance detection.
Clearances between rotor blade tips and casings in turbomachinery such as steam turbine engines change during and following transient events and affect turbomachinery/engine performance. In a more specific example, axial and radial clearances inside steam turbines between rotors and stators have been limiting factors on size, start-up, loading, and shutdown of steam turbines. Currently, conservative clearances and transition times are used to minimize contact between steam turbine stators and rotors.
It would be desirable for a clearance sensing system to have high mechanical strength to tolerate various vibration, temperature, and pressure conditions in turbomachinery installation and maintenance and to have thermal properties that are insensitive to the environment. In addition, turbine clearances are sometimes asymmetric, so it is desirable that a clearance sensing system measure clearances at multiple locations. It would also be desirable to have a durable system and technique to provide a more compact steam turbine with faster start-up capabilities.